The rubber hand illusion

Experiment with a rubber hand involves placing the subject at the table, which is a realistic rubber brush. One of the hands of the party while hiding behind the screen, and the main condition of the experiment is focusing on the artificial arm. Then the assistant starts synchronously stroking both hands with two tassels. After a few minutes of the test tactile sensation localized to a greater extent in the field of rubber brush.

Italian neuroscientists have analysed the physiological process that underlies the illusion of the rubber hand.

In the new work, the researchers repeated the experiment while observing electrical activity in the brain of participants. To do this, they used the technique of transcranial magnetic stimulation (TMS) — this non-invasive technique allows to stimulate the cerebral cortex with short magnetic pulses. Based on the feedback from the site, Innervate the hand movements, the authors made a conclusion about the level of the action potential in the local neurons.

The results showed that during the experiment, electrical activity of cells in the premotor cortex related to the hand of the subjects decreased sharply. According to scientists, this reaction says about the readiness of the brain to stop providing motor function of the limb. “The brain no longer considers the hand as a part of the body, and we lose the ability to use it”, commented the findings co-author with Francesca, Garbarini (Francesca Garbarini).

A similar illusion occurs when the brain damage, e.g. stroke patients. Such a person may be absolutely convinced that due to illness paralyzed limb does not belong to him — instead, he considers it the property of someone else’s limb. It is expected that the study will help in improving methods of rehabilitation of such patients. In addition, it can be useful in the study of other disorders associated with the violation of the scheme of the body.